arXiv 2409.197832024-09cond-mat.mtrl-scicond-mat.mes-hall

方向锁定异质外延与结构调制范德瓦尔材料

Directionally Locked Heteroepitaxy with a Structurally Modulated van der Waals Material

Princeton University（普林斯顿大学）；Princeton Materials Institute（普林斯顿材料研究所）；Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；University of the Basque Country (UPV/EHU)（巴斯克大学）；Boston College（波士顿学院）；The Hong Kong University of Science and Technology（香港科技大学）；Indian Institute of Technology Guwahati（印度理工学院古瓦哈提分校）；National Institute for Materials Science（日本国立材料研究所）；Centro de Física de Materiales (CSIC-UPV/EHU)（材料物理中心）；Université de Sherbrooke（舍布鲁克大学）

Nitish Mathur, Guangming Cheng, Francesc Ballester, Gabrielle Carrel, Vincent M. Plisson, Fang Yuan, Jiangchang Zheng, Caiyun Chen, Scott B. Lee, Ratnadwip Sing… 展开作者

Nitish Mathur, Guangming Cheng, Francesc Ballester, Gabrielle Carrel, Vincent M. Plisson, Fang Yuan, Jiangchang Zheng, Caiyun Chen, Scott B. Lee, Ratnadwip Singha, Sudipta Chatterjee, Kenji Watanabe, Takashi Taniguchi, Kenneth S. Burch, Berthold Jäck, Ion Errea, Maia G. Vergniory, Nan Yao, Sanfeng Wu, Leslie M. Schoop

备注：: 25 pages, 6 figures

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AI总结：

通过结构调制范德瓦尔TaCo2Te2基底的晶格不稳定性，实现对对称不匹配体材料CoxTey的生长与对齐，通过热处理诱导表面扩散和横向生长，实现界面方向锁定。

摘要：

通过原位加热透射电镜研究，发现TaCo2Te2基底在~523K时出现Peierls-like晶格不稳定性，经热处理后，CoxTey异质层在TaCo2Te2范德瓦尔层上发生热诱导表面扩散和主导横向生长。温度依赖的选区电子衍射图案显示，准范德瓦尔CoxTey/TaCo2Te2异质界面通过沿TaCo2Te2晶格不稳定性轴对齐较大的层间晶格不匹配，实现方向锁定，同时保持正交方向的强晶格匹配。该异质结构表现出精确的层间对齐，沿晶格不稳定性轴出现一维晶格非谐波，源于结构畸变以适应晶格不匹配应变。此外，TaCo2Te2界面重构回畸变相稳定了异质界面的晶格锁定，这些发现鼓励利用晶格不稳定性指导外延以扩展材料多样性，设计和预测新型多维异质结构。

英文摘要：

Precise orientation of symmetry-mismatched epilayers on van der Waals (vdW) substrates via heteroepitaxy has commonly been achieved through surface treatment processes to accommodate weak interlayer registry and bonding strength, thereby limiting the range of material combinations for heterostructure design. In this study, we investigate the influence of lattice instabilities in a structurally modulated vdW TaCo2Te2 substrate on the growth and alignment of a symmetry-mismatched bulk CoxTey epilayer using in situ heating in a transmission electron microscope (TEM). We show that a Peierls-like lattice instability occurs in TaCo2Te2 at a transition temperature of ~523 K, which was corroborated by phonon calculations. Post-heat-treated samples reveal a thermally induced surface diffusion process and the dominant lateral growth of the CoxTey epilayer on the TaCo2Te2 vdW layers, as observed in cross-sectional TEM images. Temperature-dependent selected area electron diffraction (SAED) patterns reveal that the quasi-vdW CoxTey/TaCo2Te2 heterointerface acquires directional locking by aligning larger interlayer lattice mismatch along the lattice instability axis of TaCo2Te2, while preserving a strong lattice matching along the orthogonal direction. This heterostructure exhibits precise interlayer registry with one-dimensional lattice incommensuration along the lattice instability axis, resulting from structural distortion to accommodate lattice-mismatch strain. Moreover, the interfacial reconstruction of TaCo2Te2 back to the distorted phase stabilizes the lattice-locking of the quasi-vdW heterointerface at elevated temperatures. These findings encourage the expansion of material diversity for designing and predicting novel multi-dimensional heterostructures by leveraging lattice instabilities to guide epitaxy.

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